Pharmacologic Application of Fourier Transform Infrared Spectroscopy: The in vivo Toxic Effect of Carrageenan

Microsomal fractions from rat brain, testes, and liver were examined by means of Fourier transform infrared spectroscopy to study the in vivo toxic effect of carrageenan administered by intraperitoneal injection. Comparison between spectra of control and treated samples clearly demonstrated important cellular damages induced by carrageenan. Lipid content was significantly enhanced in the testes and brain. The length of the acyl chains largely increased, and cholesterol ester accumulation occurred as a consequence of lipid peroxidation, particularly in the brain. Absorption intensity in the amide I and II regions was increased in the brain and testes. Conformational structure of membrane proteins was changed as shown by the large decrease in liver β-sheet structures. The phospholipid level was more significantly enhanced in the brain than in the testes. We observed in liver both an important loss in glucidic structures and a noticeable glycogen depletion. Thus, Fourier transform infrared spectroscopy appears to be a useful tool to rapidly monitor the chemical alterations induced by carrageenan on different organs. Moreover, a correlation between the spectroscopic method and the biochemical data was discussed. Further experiments should be conducted to investigate the spectral features characteristic of the various tissue types within each organ and to explore new markers for oxidation and/or inflammation.